LCRA Water Management Plan
In 2012, LCRA filed an application to amend its 2010 Water Management Plan (WMP) as previously required by the Texas Commission on Environmental Quality (TCEQ).
In 2013, the TCEQ Executive Director (ED) determined it was necessary to update naturalized streamflows in the Colorado River Basin in order to include more recent severe drought data in evaluating the application. The ED’s staff has completed its review and the ED is proposing a very comprehensive drought management regime which includes more stringent curtailment curves with a higher limit on when interruptible water releases would be completely curtailed depending on the severity of drought conditions.
Under the application review process, the ED’s draft WMP recommendation has been provided to LCRA for its review and comment at this time. The ED is not soliciting public comment on the draft recommendation during this point in the review process. However, after LCRA reviews the ED’s proposal, the ED intends to provide an opportunity for informal public review and comment in the fall.
Summary of the ED’s proposal:
ED Evaluation- Focus on More Comprehensive Management of Water Supply
- ED staff updated the existing 1940-1998 Water Availability Model (WAM) naturalized streamflows and extended the WAM period of record from 1940-2013
- Proposed new management strategy that is responsive to changing conditions to provide more protection for firm customers
- Review was based on LCRA’s 2012 WMP application. If LCRA’s operations change as a result of new permits or amendments, such as the downstream off-channel reservoir, LCRA would need to amend its WMP to reflect those changes.
What is the ED’s Proposed Strategy?
- Include a drought management regime with more checks and balances
- ED's comprehensive approach accounts for both extraordinary and less severe droughts and for normal conditions. Includes the following:
- Specific criteria to determine whether the lakes are in extraordinary drought, less severe droughts, or normal conditions.
- A range of trigger options for normal conditions
- Four looks during the year to determine how much interruptible water to release. Evaluated on a rolling annual basis to account for changing conditions.
- A more stringent cut-off floor for interruptible supply for a margin of safety.
- Protect firm demands by raising the level at which LCRA supplies interruptible stored water. Allows the lakes to be higher going into droughts. Reduces the likelihood of dropping below 600,000 acre-feet due to interruptible agricultural releases.
How does it compare with LCRA’s 2012 application?
- Used updated data to model whether LCRA’s proposed interim curtailment curves for interruptible releases were adequate during extraordinary and less severe drought conditions and normal conditions.
- LCRA’s 2012 WMP application would allow the modeled combined storage to drop below 600,000 acre-feet during the extraordinary drought conditions experienced in the current drought and the drought of the 1950s. Therefore, more robust drought management during extraordinary conditions is needed, including more stringent interruptible cut-off limits.
- Both LCRA's 2012 WMP application and a normal conditions curtailment curve would allow the modeled combined storage to drop near or below 900,000 acre-feet during less severe droughts. Therefore, a more stringent curtailment curve is needed during less severe drought conditions.
- LCRA’s 2012 WMP application would allow the modeled combined storage to drop to near 600,000 acre-feet in 1964 and below 600,000 acre-feet in 1984 under normal conditions. Therefore, interruptible releases under normal conditions should be adjusted to protect firm demands.
What would have happened in 2011 with the ED’s proposal in place?
- Using the updated models, the ED’s proposed extraordinary drought trigger of 1.4 MAF would result in over a 50 percent reduction in the amount of stored water released for interruptible customers.